石羊河流域咸水灌溉对土壤物理性质的影响

Influences of saline water irrigation on soil physical properties in Shiyang River Basin

为揭示咸水灌溉对土壤水力特性的影响机制,探求西北内陆干旱地区的合理灌溉模式,对石羊河流域中游地区开展制种玉米咸水灌溉田间试验,通过设置4种灌溉水矿化度水平(0.71,3.00,6.00,9.00 g/L),研究土壤盐分对土壤容重、孔隙度、质地和饱和导水率的影响.研究结果表明:对土壤进行咸水灌溉会引起土壤容重、孔隙度的改变,从而改变土壤饱和导水率.随着灌水次数的增多,各个处理土壤容重都越来越大,孔隙度越来越小,从而使得饱和导水率越来越小.此外咸水灌溉还会引起土壤质地的改变,特别是黏粒含量的增大,会使土壤饱和导水率减小.研究成果对咸水资源的高效利用及农业的可持续发展,具有重要的理论意义和实用价值.

To reveal the regulation mechanism of saline water irrigation on soil hydraulic properties and to exploit proper irrigation schedules in arid areas in Northwest China,a series of field experiments are conducted in the middle area of Shiyang River Basin by using irrigation water with four salinity levels( 0.71,3.00,6.00 and 9.00 g/L),the effects of salt content on soil bulk density,porosity,texture,and saturated hydraulic conductivity are identified. The results indicate that the soil bulk density increases significantly but the soil porosity decreases with increasing irrigation water salinity,thus the saturated hydraulic conductivity is changed against irrigation water salinity as well. Additionally,the soil clay content increases notably under the condition of saline water irrigation. These findings provide a new insight into understanding of the response of soil hydraulic properties to saline water irrigation.